CN105546508A - Main steam temperature control system and method for thermal power plant based on event-triggered mechanism - Google Patents

Abstract

The invention discloses a thermal power plant main steam temperature control system and method based on an event trigger mechanism. The control system includes an outer loop predictive control loop and an inner loop PID control loop; the inner loop PID control loop includes secondary detection loops connected in sequence Transmitters, secondary controllers, actuators and desuperheaters; the outer loop predictive control loop includes the main steam temperature object, the main detection transmitter, the main controller and the entire inner loop PID control loop connected in sequence, The main controller includes a reference trajectory introducer, an online corrector, an event trigger, a predictive modeler, a comparator, and an optimization calculator; the event trigger can filter input signals, and determine Decide whether to send the control signal at the current moment to the actuator. Based on an event trigger mechanism, the invention can only send signals satisfying conditions without affecting system stability, thereby reducing network transmission pressure and improving system life.

Description

Main steam temperature control system and method of thermal power plant based on event trigger mechanism

technical field

The invention belongs to the technical field of thermal power plant control, and in particular relates to a thermal power plant main steam temperature control system and method based on an event trigger mechanism.

Background technique

Since the reform and opening up, the economy has developed rapidly, but it has also brought about increasingly serious problems of environmental pollution and energy consumption. Among them, the power industry is particularly serious, especially the continuous construction of large-capacity generator sets, and it is an urgent need to improve operating efficiency and economy. Thermal power generation refers to the general term for using the heat generated by the combustion of coal and other fuels to heat water, turning the water into high-temperature, high-pressure steam, and then driving the generator to generate electricity by the steam; thermal power generating units mainly include boilers, steam turbines, power generation Equipment such as machine, coal mill, primary fan and DCS control system; the coal pulverizer grinds coal into coal powder, and the primary fan provides primary air with a certain pressure and flow rate to dry the coal powder and send it to the boiler furnace. The powder burns in the furnace and transfers the released heat to the water, which heats the water into steam at a certain temperature and pressure, which is output to the steam turbine, which converts the energy of the steam into mechanical energy and drives the generator to generate electricity. Coordinated control means that the two subsystems of boiler control and steam turbine control are controlled as a whole and coordinated with each other, so that the boiler and steam turbine can quickly adapt to the needs of power grid load changes, and jointly maintain safe and stable operation of the unit. Among them, the main steam temperature of the boiler (i.e. the main steam temperature) is an important factor affecting the thermal efficiency of the thermal power plant. If it is too high or too low, it will affect the safe and economical operation of the unit. The temperature can maintain a small fluctuation range to increase the set value of the main steam temperature, thereby achieving higher thermal efficiency. As high-parameter and large-capacity units gradually participate in power grid peak regulation, the load of the unit will change greatly, and the temperature of the main steam will also undergo drastic changes. Optimizing the main steam temperature prediction control method and improving the control accuracy and stability can reduce the occurrence of pipe burst accidents and improve the unit's rapid response ability to variable loads, which is of great significance to the long-term safe and economical operation of the unit. Today, with the rapid development of computer technology, the proposal and application of many advanced control methods provide a good inspiration for this.

At present, the conventional main steam temperature control in thermal power plants generally combines strategies such as feed-forward compensation and cascade control systems, and the design method of the cascade control system is: the main and secondary controllers use PID (proportional-integral-derivative) controllers, And because the main steam temperature control object has a large delay and inertia, the main controller adopts the PID (proportional-integral-derivative) control law, and the secondary controller generally adopts PI (proportional-integral) or P (proportional) control. According to the law, the secondary controller receives the pilot steam temperature signal and the output signal of the main controller. When the superheated steam temperature rises, the output of the main controller decreases, the output of the secondary controller increases, the amount of desuperheating water increases, and the superheated steam temperature decreases. In the case that both the primary and secondary controllers have PI control laws, the input deviations of the primary and secondary controllers are both zero. Therefore, it can be considered that the output of the main controller is the given value of the leading steam temperature.

Please refer to Fig. 1, the above-mentioned cascade control system has two inner and outer loops, the outer loop consists of the main steam temperature object 10, the main steam temperature transmitter (main detection transmitter) 11, the main controller 12 and the entire inner loop Composition, the inner loop includes the pilot steam temperature transmitter (sub-detection transmitter) 20, the sub-controller 21, the actuator 22, the desuperheating water regulating valve 23, the desuperheater 24 and the superheater 25, 26, etc., the inner loop It is a single-loop control system composed of the pilot steam temperature output by the pilot steam temperature transmitter 20 as the adjusted quantity and the desuperheater 24 as the control object. In addition, the inner loop is also a follow-up control system, which requires the output of the main controller 12 of the outer loop as a set value, and uses the output of the sub-controller 21 to control the actuator 22 to realize the control of the desuperheater 24 . Because the delay and inertia of the control object of this system are small, its control process is stable. When the desuperheating water is disturbed or the steam temperature at the outlet of the superheater after the desuperheater 24 is changed, which causes the change of the steam temperature before the pilot, the system can be adjusted in time to stabilize quickly and reduce the influence of the disturbance, especially the disturbance of the desuperheating water on the superheated steam temperature. Influence; Compared with the inner loop, the outer loop is a low-speed loop, and its main task is to maintain the main steam temperature equal to the given value. The main steam temperature has complex dynamic and strong coupling characteristics. The conventional PID control described above only focuses on the relationship between a single input and output variable in the control loop, but cannot compensate the relationship between strongly coupled or sub-strongly coupled input and output variables. In actual operation, on the one hand, due to the continuous adjustment of the secondary controller, the actuators such as control valves are frequently operated, which reduces the service life; on the other hand, this conventional main steam temperature control strategy adopts fixed parameters or segmented PID The construction of the controller does not fully consider the influence of the model change of the main steam temperature under variable loads, and the control effect will still be very unsatisfactory, seriously affecting the economy and safety of the unit.

Predictive control is a computer control technology developed in the actual industrial process. Its biggest advantage is that it does not require high model accuracy and has good tracking performance. It is more suitable for the control of complex industrial processes, especially for large-delay controlled systems. Automatic control of the process. The controlled object of the main steam temperature is also a large delay system. The "advanced" control of predictive control is an effective means to improve the quality of the main steam temperature control. ZL201310167926.5, proposed the dynamic matrix control of the main steam temperature - Proportional Integral Derivative Control (DMC-PID) cascade control method. Compared with the conventional PI control, the setting range of the control parameters of the fractional PI control is larger, the controller can control the controlled object more flexibly, and the control effect is better. However, it has not been found that the traditional thermal power plant main steam temperature PID control method, predictive control The literature and reports that the method integrating event triggering mechanism is applied to the main steam temperature control of thermal power plant boilers.

Contents of the invention

In order to solve the above problems, the present invention discloses a thermal power plant main steam temperature control system and method based on an event trigger mechanism, which can integrate the traditional thermal power plant main steam temperature PID control method, predictive control, and event trigger mechanism into one. The temperature control system is optimized so that the control of the main steam temperature has strong stability and robustness, and the operation of the actuator is determined through the judgment of the event triggering conditions to ensure the stable energy-saving operation and service life of the unit.

The present invention adopts following design scheme:

A thermal power plant main steam temperature control system based on an event trigger mechanism, including an outer loop predictive control loop and an inner loop PID control loop; the inner loop PID control loop includes a secondary detection transmitter, a secondary controller, an execution and the desuperheater; the outer loop predictive control loop includes the main steam temperature object connected in sequence, the main detection transmitter, the main controller and the entire inner loop PID control loop, and the main controller includes a reference trajectory An introducer, an online corrector, an event trigger, a predictive modeler, a comparator, and an optimization calculator, one input end of the reference trajectory introducer and the online corrector is connected to the main detection transmitter Output terminal, the output terminal of the online corrector is connected to the input terminal of the event trigger, the output terminals of the reference track introducer and the event trigger are connected to the input terminal of the comparator, and the comparison The output end of the controller is connected to the input end of the optimization calculator, the output end of the optimization calculator is connected to the input end of the secondary controller and the input end of the predictive modeler, and the output end of the predictive modeler is connected to to the other input of the online corrector.

Further, event trigger rules or trigger functions are established in the event trigger:

G(y _p (k), y _p (k+i))=||y _p (k)-y _p (k+i)||-σ, where, G(y _p (k), y _p ( k+i)) is the trigger function between the output signal y _p (k+i) of the online corrector at the current moment (k+i) and the output signal y _p (k) of the previous moment, and σ is the The bounded positive number of (0,1), |||| represents the norm, and i=1,2,…, are positive integers.

Further, when the trigger function is less than or equal to 0 or the signal received by the event trigger at the current moment does not satisfy the event trigger rule, it is considered that no "event" has occurred, and the output terminal of the event trigger has no output signal ; When the trigger function is greater than 0 or the signal received by the event trigger at the current moment satisfies the event trigger rule, it is considered that the "event" is triggered, and the output terminal of the event trigger will output the signal received at the current moment signal of.

Further, the inner loop PID control loop also includes a desuperheating water pipeline communicated with the desuperheater, and a desuperheating valve arranged on the desuperheating water pipeline and connected to the actuator.

A kind of above-mentioned method based on event triggering mechanism main steam temperature control system of thermal power plant, comprises the following steps:

(1) The output signal of the main air temperature object is periodically sampled through the main detection transmitter working in the time-driven mode;

(2) the output signal obtained by sampling in the step (1) is transmitted to the reference trajectory introducer and the online corrector of the master controller;

(3) The online calibrator corrects the prediction signal at the current moment output by the prediction modeler of the main controller according to the received output signal, and transmits the corrected signal to the main controller Event trigger; at the same time, the reference trajectory introducer determines the reference trajectory of the output signal according to the received output signal and the set value of the main air temperature object inside;

(4) The event trigger selectively outputs the corrected signal according to its internal trigger function or event trigger rule, and the result of the selective output and the reference trajectory output by the reference trajectory introducer are both sent to the comparator of the main controller;

(5) The optimization calculator of the main controller performs rolling optimization on the output signal of the comparator, and outputs the result of the optimization calculation to the secondary controller and the predictive modeler;

(6) Periodically sample the output signal of the desuperheater through the secondary detection transmitter working in a time-driven manner, and transmit the sampled output signal to the secondary controller;

(7) The secondary controller controls the action of the actuator according to the output signal of the optimization calculator and the output signal of the secondary detection transmitter.

Further, in the step (4), the public operation formula for the event trigger to selectively output the corrected signal according to its internal trigger function or event trigger rule is as follows:

||x _p ((k+i)h)-x _p (kh)||-σ≤0

Among them, σ is a normal number belonging to (0,1), h is the sampling period, (k+i)h is the (k+i)th sampling period, kh is the kth sampling period, i=1,2, ..., is a positive integer, x _p ((k+i)h) is the signal output by the online corrector at the current moment, x _p (kh) is the signal output by the online corrector at the previous moment, and σ is A bounded positive number, |||| represents the norm;

And when the output signal of the online corrector at the current moment satisfies the above formula, it is considered that no "event" has occurred, the output of the event trigger has no output signal, and the output of the optimization calculator is not updated; when the When the output signal of the online corrector at the current moment does not satisfy the above formula, it is considered that an "event" is triggered, and the output terminal of the event trigger will output the output signal of the online corrector at the current moment, and the optimization calculation The output of the controller is updated.

Further, the reference trajectory determined by the reference trajectory introducer is:

x _r ((k+i)h)=a ⁱ x ₁ (kh)+(1-a ⁱ )x _d (kh), where a ⁱ =exp(-h/λ)∈(0,1), h is the sampling period, λ is the time constant, x _r ((k+i)h) is the reference trajectory; x ₁ (kh) is the output signal of the main detection transmitter at the current moment; x _d (kh) is the The set value of the main air temperature object at the current moment.

Further, step (7) also includes: the actuator adjusts the desuperheating valve provided on the desuperheater water pipeline connected with the desuperheater according to the control of the sub-controller, so as to adjust the water flow into the desuperheater. The flow rate of the desuperheated water in the desuperheated water pipeline.

Further, the secondary controller adopts PI or P control law.

Compared with the prior art, the main steam temperature control system and method of the thermal power plant based on the event trigger mechanism of the present invention have the following beneficial effects:

(1) The secondary controller of cascade control can adopt traditional PI or P control, and the main controller is replaced by a predictive controller based on event triggers and predictive modelers, which can be controlled according to the current control input and historical data of the system. Predict, get the future output value, then compare the preset value, and perform rolling optimization to get the current control input channel of the sub-controller, the sub-controller receives the output of the main controller as the set value, and uses the output signal of the sub-controller To control the actuator and control the opening of the desuperheating valve, so as to realize the adjustment of the desuperheating water flow, so that the main steam temperature reaches the set value, so as to realize the optimal control, so that the control of the main steam temperature has strong stability and robustness and more adaptable to actual production.

(2) Introduce an event trigger in the main controller. The event trigger is used to judge the output value based on the synchronization data received at the current moment and its internal event trigger mechanism rules or trigger functions, and the latest output value of the event trigger The comparison with the latest received value determines the next output value of the main controller, which can reduce the fluctuation range of the main steam temperature, improve the adjustment quality, and reduce the adjustment times of the adjustment valve, thereby increasing the service life.

Description of drawings

Fig. 1 shows the structure schematic diagram of the main steam temperature cascade control system of the traditional thermal power plant;

Fig. 2 shows the structural representation of the master controller that adds event trigger according to the specific embodiment of the present invention;

Fig. 3 is a schematic structural diagram of a thermal power plant main steam temperature control system based on an event trigger mechanism applying the main controller shown in Fig. 2 .

detailed description

The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings.

Because in the traditional control method of the main steam temperature of the thermal power plant shown in Figure 1, the continuous adjustment of the secondary controller makes the actuators such as control valves operate frequently, reducing the service life, so in the thermal power plant main steam temperature based on the event trigger mechanism of the present invention In the temperature control system, in consideration of stability and safety, priority is given to reducing the execution times of the actuator.

Fig. 2 is a schematic structural diagram of a master controller with an event trigger designed based on reducing the execution times of the executor in the present invention. The main controller designed in the present invention has a prediction function, and can predict according to the current control input and historical data of the system to obtain future output values, then compare preset values, and perform rolling optimization to obtain current control input. Specifically, it is composed of a reference trajectory introducer 121, an online corrector 122, an event trigger 123, an optimization calculator 124, a predictive modeler 125, and a comparator 126, so as to realize the functions of predictive control, feedback correction, on-demand trigger, and rolling optimization.

(1) The predictive modeler 125 mainly realizes predicting the future control input value of the controlled process based on the historical control input of the controlled process based on its internal predictive model for describing the dynamic characteristics of the process.

(2) The reference trajectory introducer 121 is used to determine the reference trajectory, that is, to determine a curve in which the measured output value of the controlled process at the current moment transitions smoothly to its set value, and the curve is the reference trajectory: y _r ( k+i)=a ⁱ y(k)+(1-a ⁱ )y _d , wherein, a ⁱ =exp(-h/λ)∈(0,1), h is the sampling period, and λ is the time constant; y _r (k+i) is the reference trajectory; y(k) is the output measurement value of the controlled process at the current moment; y _d is the set value of the controlled process.

(3) The online corrector 122 is used to perform feedback correction on the output of the predictive modeler 125 according to the output measurement value of the controlled process at the current moment. There is an error e(k), so, similar to the feedback system, the output of the predictive modeler needs to be corrected in time.

(4) The setting of the event trigger 123 is to reduce the number of execution tasks of the executor in the controlled process, so as to realize the control task "on demand" under the premise of keeping the control system stable.

An event trigger mechanism criterion or trigger function is established inside the event trigger, and the signal is screened according to this criterion or trigger function, and finally the satisfied signal can be sent to the controlled process, thereby controlling the execution of the regulating valve in the controlled process device action. The basic idea of the design of the event trigger mechanism criterion or trigger function is: calculate the function value between the received signal at the current moment and the output signal at the previous moment, and compare this value with the preset threshold function , if greater than zero, the "event" is considered to have been triggered, otherwise the new received signal is not transmitted. The event trigger mechanism criterion or trigger function defined in the present invention is: G(y _p (k), y _p (k+i))=||y _p (k)-y _p (k+i)||- σ,

Among them, y _p (k+i) is the signal output by the online corrector 122 after feedback correction received by the event trigger 123 at the current moment (k+i), and y _p (kh) is the signal output by the event trigger 123 at the last moment k The received online corrector 122 feeds back the corrected output signal, σ is a bounded positive number, |||| represents a norm, i=1, 2,..., is a positive integer, G(y _p (k), y _p (k+i)) is the trigger function between y _p (k+i) and y _p (kh). In this example, if the trigger function is less than or equal to 0, it is considered that no "event" has occurred, and the newly received signal y _p (k+i) by the event trigger 123 will not be output; if the value of the trigger function is greater than 0, it is considered to have occurred "event", the event trigger 123 will output the newly received signal y _p (k+i)), which is used to update the signal output by the optimization calculator 124, and adjust the actions of actuators such as control valves in the controlled process, thereby Control the entire system. In this example, the value range of the parameter σ can be selected according to the Lyapunov stability analysis theory, for example, σ is a normal number belonging to (0,1). After adding the event trigger mechanism, the running times will be reduced without affecting the stability of the system.

(5) The optimization calculator 126 is used to perform rolling optimization according to the output of the comparator 126: the control prediction value at the current moment output by the optimization calculator 126 is actually based on the controlled process (i.e. the control target, which is essentially the current moment of the controlled process) output measured value), prediction model and the current situation of the whole system are calculated, so at the next moment, the optimization calculator 126 will optimize according to the optimization target and the current situation of the system that has already been running, and calculate the control prediction of the next moment value.

FIG. 3 is a schematic structural diagram of the main steam temperature cascade predictive control system of a thermal power plant based on an event-triggered mechanism using the main controller shown in FIG. 2 according to the present invention.

Taking the main steam temperature control system of a thermal power plant as an example, the present invention provides a main steam temperature control system of a thermal power plant based on an event trigger mechanism, including a control network formed by an outer loop predictive control loop and an inner loop PID control loop; the inner loop The ring PID control loop includes a secondary detection transmitter 20, a secondary controller 21, an actuator 22, and a desuperheater 24 connected in sequence; the outer loop predictive control loop includes a main steam temperature object 10, a main detection transmitter device 11, main controller 12 and the entire inner loop PID control loop, the main controller includes a reference trajectory introducer 121, an online corrector 122, an event trigger 123, a predictive modeler 125, a comparator 126 and an optimization Calculator 124, one input end of the reference trajectory introducer 121 and the online corrector 122 are connected to the output end of the main detection transmitter 11, and the output end of the online corrector 122 is connected to the The input terminal of the event trigger 123, the output terminals of the reference trajectory introducer 121 and the event trigger 123 are connected to the input terminal of the comparator 126, and the output terminal of the comparator 126 is connected to the optimization calculator 124, the output of the optimization calculator 124 is connected to the input of the secondary controller 21 and the input of the predictive modeler 125, and the output of the predictive modeler 125 is connected to the online The other input terminal of the corrector 122 .

In this embodiment, the main controller 12 and the sub-controller 21 form a cascade predictive control strategy, the sub-controller 21 adopts PI or P control, and the main controller 12 is a predictive control with a built-in event trigger 123, and the sub-controller 21 The output of the main controller 12 is received as a set value, and the output of the secondary controller is used to control the actuator 22, thereby controlling the opening of the water reducing valve (not shown in FIG. 3 ) connected to the actuator 22 to realize the The adjustment of the desuperheating water flow in the desuperheating water pipeline of the desuperheater 24 makes the temperature of the main steam of the thermal power plant boiler reach the set value, thereby realizing optimal control.

It can be seen from the above that the main steam temperature control system of the thermal power plant based on the event trigger mechanism of the present invention introduces the event trigger mechanism into the outer loop predictive control loop of the cascade control system, and the error between the output of the predictive model and the output of the process control is used. Adjust the parameters of the main controller 12, and finally obtain a suitable and stable system with the error tending to zero, which can reduce the fluctuation range of the main steam temperature, improve the adjustment quality, and at the same time reduce the number of operations of the actuator, that is, reduce the adjustment of the temperature reduction valve The number of times improves the service life of the actuator and the desuperheating valve; in addition, the main steam temperature control system of the thermal power plant based on the event trigger mechanism of the present invention combines the advantages of cascade control and network control, and also has the function of predictive control Advantages, the accuracy of the process mathematical model is not high, the tracking is good, the error is robust, and it is more suitable for actual production.

The present invention also provides a method for controlling the temperature of the main steam in a thermal power plant based on an event trigger mechanism by the main steam temperature control system of the thermal power plant, comprising the following steps:

Step 1: periodically sample the output signal y ₁ (t) of the main steam temperature object (i.e. the main controlled object) 11 through the main detection transmitter (i.e. the main steam temperature transmitter) 11 working in a time-driven manner , to obtain the sampling signal x ₁ (t) at the current moment;

The second step: the main detection transmitter 11 outputs the signal x ₁ (kh) to the online corrector 122 and the reference trajectory introducer 121;

Step 3: The online corrector 122 corrects the current prediction signal x _m ((k+i)h) output by the prediction modeler 125 according to the received signal x ₁ (kh), and converts the corrected signal x _p ((k+i)h) is transmitted to the event trigger 123; at the same time, the reference trajectory introducer 121 determines that the received signal x ₁ (kh) is sent to its internal main air temperature object set value x _d ( kh) smooth transition reference trajectory x _r ((k+i)h)=a ⁱ x ₁ (kh)+(1-a ⁱ )x _d (kh), where a ⁱ =exp(-h/λ)∈ (0,1), h is the sampling period, λ is the time constant;

Step 4: The event trigger 123 selectively outputs the corrected signal x _p ((k+i)h) according to its internal trigger function or event trigger rule. For the event trigger mechanism adopted by the present invention (i.e. The specific formula for the operation of trigger function or event trigger rule) is as follows:

||x _p ((k+i)h)-x _p (kh)||-σ≤0

Among them, σ is a normal number belonging to (0,1), h is the sampling period, (k+i)h is the (k+i)th sampling period, i=1,2,... are positive integers, x _p ((k+i)h) is the signal output by the online corrector 122 at the current moment, x _p (kh) is the signal output by the online corrector 122 at the last moment, and |||| represents the norm; when the online corrector When the signals x _p ((k+i)h) and x _p (kh) output twice before and after 122 satisfy the above formula, then it is considered that no "event" has occurred, and the output terminal of the event trigger 123 has no output signal; when the When the signals x _p ((k+i)h) and x _p (kh) output twice before and after the online corrector 122 do not satisfy the above formula, it is considered that an "event" is triggered, and the output terminal of the event trigger 122 will output all The output signal x _p ((k+i)h) of the online corrector at the current moment; the result selectively output by the event trigger 122 and the reference trajectory x _r ((k+i)h output by the reference trajectory line introducer 121 ) are all sent to the comparator 126;

Step 5: The optimization calculator 124 performs rolling optimization on the output signal compared by the comparator 126, and outputs the result u ₁ (kh) of the optimization calculation to the secondary controller 21 and the predictive modeler 125. At this time, the main controller The output value of 12 is used as the setting value of the sub-controller 21, and the prediction modeler 125 will output the prediction signal at the next moment according to u ₁ (kh);

Step 6: The auxiliary detection transmitter (i.e. the leading steam temperature transmitter) 20 periodically samples the output signal y ₂ (t) of the desuperheater 24 (i.e. the auxiliary controlled object) to obtain the sampling signal at the current moment x ₂ (t), and the output signal x ₂ (kh) obtained by the secondary detection transmitter 20 according to the signal x ₂ (t) is transmitted to the secondary controller 21 through the inner loop PID control loop;

Step 7: The sub-controller 21 outputs the control signal to the actuator 22 according to the signal x ₂ (kh) and u ₁ (kh), so as to control the action of the actuator 22 (heat reduction valve), specifically, when the event triggers When the controller 123 has no output, the output result u ₁ (kh) of the optimization calculator 124 is not updated, the sub-controller 21 maintains the original control over the actuator 22, and the actuator 22 has no switching action; when the event trigger 123 outputs x _p ( (k+i)h), the output u ₁ (kh) of the optimization calculator 124 is updated, the sub-controller 21 controls the actuator 22 again, and the actuator 22 switches actions;

Step 8: Go back to the first step.

The above description is only an implementation example of the present invention, and is not intended to limit the present invention. The present invention is especially applicable to remote cascade control. All equivalent replacements made within the principle of the present invention shall be included in the protection scope of the present invention. The content not described in detail in the present invention belongs to the prior art known to those skilled in the art.

Claims (9)

1. based on thermal power plant's Control on Main-steam Temperature of event trigger mechanism, it is characterized in that, comprise outer shroud predictive control loop and inner ring pid control circuit, described inner ring pid control circuit comprises the pair connected successively and detects transmitter, submaster controller, actuator and attemperator, described outer shroud predictive control loop comprises the Stream temperature object connected successively, main detection transmitter, master controller and whole described inner ring pid control circuit, described master controller comprises reference trajectory introducer, on-line correction device, event trigger, forecast model device, comparator and optimization calculator, an input of described reference trajectory introducer and described on-line correction device is all connected to the output of described main detection transmitter, the output of described on-line correction device is connected to the input of described event trigger, the output of described reference trajectory introducer and described event trigger is all connected to the input of comparator, the output of described comparator is connected to the input optimizing calculator, the output of described optimization calculator is connected to the input of described submaster controller and the input of described forecast model device, the output of described forecast model device is connected to another input of described on-line correction device.

2. thermal power plant according to claim 1 Control on Main-steam Temperature, is characterized in that, setting up in described event trigger has event triggering rule or trigger function: G (y _p(k), y _p(k+i))=|| y _p(k)-y _p(k+i) ||-σ, wherein, G (y _p(k), y _p(k+i)) be the output signal y of current time (k+i) of described on-line correction device _p(k+i) with the output signal y in a upper moment _ptrigger function between (k), σ for belonging to the bounded positive number of (0,1), || || represent norm, i=1,2 ..., be positive integer.

3. thermal power plant according to claim 2 Control on Main-steam Temperature, it is characterized in that, when described trigger function be less than or equal to 0 or described event trigger current time receive signal do not meet described event triggering rule time, then think and " event " does not occur, the output non-output signal of described event trigger; When described trigger function is greater than 0 or the signal that receives of described event trigger current time meets described event triggering rule, then think and trigger " event ", the output of described event trigger can export the signal that described current time receives.

4. thermal power plant according to claim 1 Control on Main-steam Temperature, it is characterized in that, described inner ring pid control circuit also comprises the desuperheating water pipeline that is connected with attemperator and is arranged on the desuperheat valve be connected on described desuperheating water pipeline and with described actuator.

5. a control method for the thermal power plant's Control on Main-steam Temperature based on event trigger mechanism according to any one of Claims 1-4, is characterized in that, comprise the following steps:

(1) output signal of main detection transmitter to main temperature object by working in time type of drive carries out periodic sampling;

(2) in the reference trajectory introducer that the output signal obtained sampling in step (1) is transferred to master controller and on-line correction device;

(3) described on-line correction device corrects according to the prediction signal of the described output signal received to the current time that the forecast model device of described master controller exports, and by the Signal transmissions after correcting to the event trigger of described master controller; Described reference locus line introducer determines the reference locus of described output signal according to the main temperature object setting value receiving described output signal and inside thereof simultaneously;

(4) described event trigger carries out selective output according to the trigger function of its inside or event triggering rule to the signal after described correction, and the reference locus that the result of described selective output and described reference locus line introducer export all sends into the comparator of main controller;

(5) the optimization calculator of described master controller carries out rolling optimization to the output signal of described comparator, and exports described submaster controller and described forecast model device to by optimizing the result calculated;

(6) pair by working in time type of drive detects transmitter and carries out periodic sampling to the output signal of attemperator, and the output signal obtained of sampling is transferred to described submaster controller;

(7) described submaster controller controls the action of actuator according to the output signal that the output signal of described optimization calculator and described pair detect transmitter.

6. control method according to claim 5, it is characterized in that: in described step (4), the public operational formula that described event trigger carries out selective output according to the trigger function of its inside or event triggering rule to the signal after described correction is as follows:

||x _p((k+i)h)-x _p(kh)||-σ≤0

Wherein, σ is for belonging to the normal number of (0,1), and h is the sampling period, and (k+i) h is (k+i) individual sampling period, and kh is a kth sampling period, i=1, and 2 ..., be positive integer, x _p((k+i) is h) signal that described on-line correction device exports at current time, x _p(kh) be the signal that described on-line correction device exported in a upper moment, σ is bounded positive number, || || represent norm;

And when described on-line correction device meets above-mentioned formula in the output signal of current time, then think and " event " does not occur, the output non-output signal of described event trigger, the output of described optimization calculator does not upgrade; When described on-line correction device does not meet above-mentioned formula in the output signal of current time, then think and trigger " event ", the output of described event trigger can export the output signal of described on-line correction device at current time, and the output of described optimization calculator upgrades.

7. control method according to claim 5, is characterized in that: the reference locus that described reference trajectory introducer is determined is:

X _r((k+i) h)=a ⁱx ₁(kh)+(1-a ⁱ) x _d(kh), wherein, a ⁱ=exp (-h/ λ) ∈ (0,1), h is the sampling period, and λ is time constant, x _r((k+i) is h) reference locus; x ₁(kh) be the output signal of described main detection transmitter current time; x _d(kh) be the described main temperature object setting value of described current time.

8. control method according to claim 5, it is characterized in that: step (7) also comprises: described actuator regulates the desuperheat valve be arranged on the desuperheating water pipeline that is connected with described attemperator according to the control of described submaster controller, to regulate the flow flowing into the ducted desuperheating water of described desuperheating water.

9. control method according to claim 5, is characterized in that: described submaster controller adopts PI or P control law.